Treasury Secretary Steve Mnuchin will tell a Senate hearing on Thursday that the U.S. economy can grow 3 percent or more if regulatory and tax reforms are enacted, according to a copy of his speech seen by Reuters.

In testimony before the Senate Committee on Banking, Housing and Urban Affairs, Mnuchin is expected to say that the Trump administration wants to reduce regulations on community banks and push ahead with overhauling mortgage lenders Fannie Mae and Freddie Mac.

"I believe that a goal of 3 percent GDP or higher economic growth is achievable if we make historic reforms to both taxes and regulation," Mnuchin will say.

Most mainstream economists believe the U.S. economy will struggle to grow more than 2 percent a year due to demographic headwinds and long-term slow productivity growth.

The Trump administration has made slow progress in enacting its economic and reform agendas and now faces an investigation by a special counsel into possible collusion between President Donald Trump's 2016 campaign team and Russia.

Mnuchin did not spell out any of the details or the time scale for the government's agenda. Financial markets and the dollar had rallied sharply after Trump's surprise election on expectations that regulations would be rolled back, but the scandal over the firing of Federal Bureau of Investigation Director James Comey hit Wall Street hard on Wednesday.

The S&P 500 and the Dow notched their biggest one-day fall since Sept. 9 as investor hopes for tax cuts and other pro-business policies faded.